Metal cutting tools



3, 1966 J. HARGREAVES METAL CUTTING TOOLS Filed July 16, 1964 United States Patent METAL CUTTING TOOLS I-ames Hargreaves, Finham, Coventry, England, asslgnor to Wickman Wimet Limited, Coventry, England Filed July 16, 1964, Ser. No. 383,100 Claims priority, application Great Britain, Aug. 1, 1963, 30,507 63 2 Claims. (Cl. 29-96) This invention relates to metal cutting tools of the kind in which a cutting tool is advanced relative to the work when cutting and is retracted slightly from the work before complete withdrawal so that no return mark is left on the work.

According to the invention, a tool of the kind specified includes a shank adapted for connection to a toolholder, a bit support mounted on the shank for movement between an operative position and an inoperative position, and biasing means urging the bit support to its inoperative position, the arrangement being such that, in use, when a bit is held in the bit support and advanced relative to the work, the pressure between the work and the bit will hold the bit support in its operative position against the action of the biasing means, but as soon as contact of the bit relative to the work ceases the biasing means will move the bit support to its inoperative position in which the bit is out of contact with the work.

A tool as specified above has the important advantage that it can be applied to a variety of existing toolholders without any modifications to the toolholder. This advantage results from the fact that the tool is self-contained and it is not necessary for the resilient means to react on the toolholder. Moreover, in the preferred embodiment the arrangement is such that the resilient means is completely enclosed by the tool throughout the range of movement of the bit support, so that there is no risk of swarf impairing the action of the resilient means.

In the accompanying drawings, FIGURE 1 is a side view illustrating one example of the invention, FIG- URES 2 and 3 are sections on the lines 2-2 and 33 in FIGURES 1 and 2 respectively, and FIGURES 4 and 5 are views at right angles to FIGURE 1 showing the tool during a cutting operation and whilst being withdrawn respectively.

Referring to the drawings, there is provided a shank 11 which is adapted for connection to a toolholder which is an existing part of a machine tool. For a facing operation the shank is secured to the toolholder (not shown) so as to extend parallel to the direction of traverse'relative to the work as illustrated, and for a tuming operation the arrangement such that the shank extends at right angles to the direction of traverse relative to the work. Other configurations of the shank relative to the bit are possible depending on the operation and machine.

The shank is of generally rectangular cross-section, but at one end is recessed to form a shelf 12 adapted to receive a support 14 for a detachable bit assembly 15. The assembly 15 forms no part of the present invention and is not therefore described in detail. Conveniently, the assembly 15 is of the form described in our Patent No. 925,617. The support 14 is formed with an integral pin 16 which extends through a bore 17 in the shelf 12 and is held in position by a washer and "ice circlip 18 so that the support 14 is angularly movable about the axis of the bore 17.

There are also formed in the bit support 14 a bore 19 parallel to the bore 17, and a bore 21 extending completely through the support at right angles to and intersecting the bore 19. Moreover, extending into the bore 19 from the shelf :is a second pin 22 which is secured relative to the shank by a locking screw 23. Bearing against the pin 22 is one end of a compression spring 24 located in the bore 21 with its other end bearing against a screw 25 closing one end of the bore 21. The other end of the bore 21 is closed by a further screw 26 which projects into the bore 19 by an adjustable amount. The screws 23, 25 and 26 and spring 24 are omitted from FIGURES 4 and 5 for clarity.

Angular movement of the bit support 14 about the axis of the bore 17 is limited by abutment between the pin 22 and the screw 26 and the spring 24 urges the bit support to an inoperative position shown in FIGURE 5 in which in use a bit carried by the support is out of contact with the work (shown at 27). During a turning or facing operation the cutting pressures between the bit and workpiece hold the bit support in its operative position against the action of the spring as shown in FIGURE 4, but as soon as contact of the cutting bit with the work ceases the bit support returns to its inoperative position. The movement of the support will of course be very small, but sufficient to prevent a return mark from being left on the work.

The tool may take a variety of other forms. In particular, the pin 22 could extend Ifrom the bit support 14 and the spring 24 and screws 25, 26 could be accommodated in the shank.

The cutting element of the bit may be an insert of any shape such as round, triangular or square adapted to be releasably clamped to the bit support, or the insert may be brazed directly to the bit support.

In a modification, the bit support is slidable on the shank between an operative position and an inoperative position.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. A metal cutting tool comprising in combination a shank adapted for connection to a tool holder, a bit support, means mounting said bit support on said shank for angular movement between an operative position and an inoperative position, a first bore formed in one of the parts constituted by the shank and the bit support, said first bore extending parallel to the axis about which the bit support moves angularly, a second bore extending through said one part and intersecting said first bore, a pin extending from the other of said parts into said first bore, a member closing one end of the second bore, and a spring acting between said member and said pin to urge said bit support to its inoperative position, the arrangement being such, that in use, when a bit is held in the bit support, and advanced relative to the work, the pressure between the work and the bit will hold the bit support in its operative position against the action of said spring, but as soon as contact of the bit relative to the work ceases, the spring will move said bit support to its inoperative position in which the bit is out of contact with the work.

2. A tool as claimed in claim 1 including an adjustable member closing the other end of said second bore and extending into said first bore, said adjustable member 32 4 limiting angular movement of said bit support with re- FOREIGN PATENTS SPect t 831d P 704,845 3/1954 Great Britain.

References Cited by the Examiner UNITED STATES PATENTS 2,525,216 10/1950 Garrand 29--96 X WILLIAM W. DYER, J R., Primary Examiner. 5 HARRISON L. HINSON, Examiner. 

1. A METAL CUTTING TOOL COMPRISING IN COMBINATION A SHANK ADAPTED FOR CONNECTION TO A TOOL HOLDER, A BIT SUPPORT, MEANS MOUNTING SAID BIT SUPPORT ON SAID SHANK FOR ANGULR MOVEMENT BETWEEN AN OPERATIVE POSITION AND AN INOPERATIVE POSITION, A FIRST BORE FORMED IN ONE OF THE PARTS CONSTITUTED BY THE SHANK AND THE BIT SUPPORT, SAID FIRST BORE EXTENDING PARALLEL TO THE AXIS ABOUT WHICH THE BIT SUPPORT MOVES ANGULARLY, TO SECOND BORE EXTENDING THROUGH SAID ONE PART AND INTERSECTING SAID FIRST BORE, A PIN EXTENDING FROM THE OTHER OF SAID PARTS INTO SAID FIRST BORE, A MEMBER CLOSING ONE END OF THE SECOND BORE, AND A SPRING ACTING BETWEEN SAID MEMBER AND SAID PIN TO URGE SAID BIT SUPPORT TO ITS INOPERATIVE POSITION, THE ARRANGEMENT BEING SUCH, THAT IN USE, WHEN A BIT IS HELD IN THE BIT SUPPORT, AND ADVANCED RELATIVE TO THE WORK, THE PRESSURE BETWEEN THE WORK AND THE BIT WILL HOLD THE BIT SUPPORT IN ITS OPERATIVE POSITION AGAINST THE ACTION OF SAID SPRING BUT AS SOON AS CONTACT OF THE BIT RELATIVE TO THE WORK CEASES, THE SPRING WILL MOVE SAID BIT SUPPORT TO ITS INOPERATIVE POSITION IN WHICH THE BIT IS OUT OF CONTACT WITH THE WORK. 